# Relationship history for MSHA mine 2101502

Current hierarchy: **Holwell Kent → N W Concrete Products Inc → N W Concrete Products**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Falls Concrete & Supply Inc → N W Concrete Products; 1950-01-01 to 1986-06-03; source msha-controller-operator-history
- **controller_controls_mine:** Sabo Les → N W Concrete Products; 1950-01-01 to 1986-06-03; source msha-controller-operator-history
- **controller_controls_operator:** Sabo Les → Falls Concrete & Supply Inc; 1950-01-01 to 1986-06-03; source msha-controller-operator-history
- **operator_operates_mine:** N W Concrete Products Inc → N W Concrete Products; 1986-06-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Holwell Kent → N W Concrete Products; 1986-06-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holwell Kent → N W Concrete Products Inc; 1986-06-04 to current/open; source msha-controller-operator-history